1. Field of the Invention
The present invention relates to a heat exchange apparatus having an outdoor unit and a plurality of indoor units in which cooling operation or heating operation can be simultaneously performed in the plural indoor units or both cooling operation and heating operation can be simultaneously performed in a mixing mode in the plural indoor units, and a refrigerating machine having the heat exchange apparatus.
2. Description of the Related Art
There is generally known a refrigerating machine (heat exchange apparatus) in which an outdoor unit and a plurality of indoor units are connected to one another through an inter-unit pipe comprising a high pressure gas pipe, a low pressure gas pipe and a liquid pipe and cooling operation or heating operation can be performed in a plurality of indoor units at the same time, or both cooling operation and heating operation can be performed in a mixing mode in a plurality of indoor units at the same time (see Japanese Patent No. 2804527).
This type of refrigerating machine has a problem that when cooling operation is carried out, the refrigerant temperature at the exit of a heat-source side heat exchanger is increased in connection with increase of the outside air temperature and thus the cooling performance is lowered. Furthermore, it has also a problem that when heating operation is carried out, the refrigerant temperature at the exit of the heat-source side heat exchanger is reduced in connection with decrease of the outside air temperature and thus the heating performance is lowered.